1. Field of The Invention
The invention relates to retention posts for use with a connector, particularly to a pair of posts adapted to be attachably fastened to an elongated housing of the connector, and respectively positioned proximate two opposite ends in the lengthwise direction.
2. The Prior Art
Retention posts of the connector incorporating through-holes in the PC board is a very popular way to secure, temporarily and/or permanently, the connector onto the board. As known, the retention post or boardlock made of metal might have good resilience to comply with deviation of the corresponding hole in the PC board for easy operation, for example, U.S. Pat. Nos. 4,681,389, 4,795,353, 4,842,552, 4,907,987, 5,024,607, 5,083,926, 5,108,312, 5,171,165, 5,244,414, 5,295,862, and 5,316,500. Unfortunately, such metal retention post requires stamping and forming process in manufacturing such metal retention post, thus increasing the cost. Additionally, metal material of such retention post is relatively more expensive than plastic material. Using the plastic post integral with the connector housing naturally is much cheaper than using the metal one, but stiffness of plastic tends to preclude deviation of position of the hole in the PC board. Anyhow, some computer manufacturers intend to use the inexpensive plastic retention post integral with the connector housing for saving cost, but still allowing reasonable deviation of the hole in the PC board. Most achievements in designing such plastic retention post are to try to reform the post for increasing resilience thereof in compliance with the deviated hole in the PC board, for example, U.S. Pat. Nos. 5,071,371 (claim 25), 5,302,134, 5,312,642, 5,334,647, 5,328,389, 5,336,110, 5,336,111, and the patent application of Ser. No. 07/929,087 filed Aug. 12, 1992.
In fact, most cases of incompatibility between the retention post of the connector and the hole in the PC board, result from warp of the housing of the connector in the lengthwise direction wherein such warp is due to shrinkage of such plastic material of the connector housing after molding process. In other words, the cold molded connector tends to be somewhat a bow-shape as shown in FIG. 1. This is the reason why in some designs, the lengthwise connector housing 2 has a center post 6 at the bottom which designedly engages a central hole 7 in the board 5 for pulling the central portion of the housing downwardly for maintaining the whole housing 2 to be fully seated on the PC board 5. From another viewpoint, because of warp of the housing 2 along such lengthwise direction of the housing 2, the centerline of the two retention posts 3 positioned proximate two opposite ends of the housing 2, is naturally moved closer to each other than those of the original design specification. Understandably, these two closer posts 3 of the connector housing 2 do not comply with the corresponding holes 4 in the PC board 5 which are located in the normal position according to the specification.
An object of the invention is to provide the connector with a post device made of the inexpensive plastic material wherein such post device can be conformably received in the corresponding hole in the PC board, on which such connected is mounted, even though there is a warp of the connector housing along its lengthwise direction.
Another object of the invention is to provide the connector with a post device made of the inexpensive plastic material wherein such post device can be detachably attached to the connector housing. As well known, the conventional plastic post integral with the housing is easily broken during shipping or handling due to its tiny dimension and its stiffness. Commonly, the whole connector should be abandoned in such situation because the damaged post is integrally molded with the connector housing. In the invention, only replacing the damaged post can be applied thereto, thus saving the cost. From another viewpoint of engineering, the post can be made by heat-resistant material rather than the common material used in the connector housing, thus being able to meet the requirements of the characters of the whole connectors, i.e., the strength and the heat-resistance of the post, and the appropriate stiffness and/or elasticity of the housing. It can be understood that in the conventional plastic post connector which includes the integral post, applying the stiff material as the post to the whole connector housing not only costs money, but also results in the problem of shortness or brittleness of the housing which is not suitable for the contacts in an interference therein. In contrast, through the present invention, the post and the housing can be respectively made of the proper plastic material different from each other to meet the respective mechanical requirements and to save the whole set's cost.